CHAPTER XXI. 



THE GLANDULAR ORGANS. 



THE LIVER. 



THE functions of the liver, as is apparent from a survey of the 

 foregoing chapters, are manifold. During embryonic life the organ 

 is intimately concerned in the production of red corpuscles, and at 

 this time already manifests its function as an excretory organ also 

 in the production of bile. After birth its haemapoietic activity 

 ceases, but it continues important as an excretory organ through 

 which the decomposition-products of haemoglobin, in so far as they 

 are not retained and utilized in the formation of new corpuscles, are 

 eliminated from the body in association with taurin, glycocoll, 

 cholesterin, and the cholalic acids. At the same time, however, the 

 liver is the seat of some of the most important syntheses which occur 

 in the animal body, and in which both anabolic and katabolic prod- 

 ucts of the metabolism are involved. We have thus seen that the 

 greater portion of urea in mammals, and of uric acid in birds and 

 reptiles, is here produced, and we have also pointed out that certain 

 aromatic substances which are formed during the process of intes- 

 tinal putrefaction or have been ingested as such are transformed 

 in the liver into conjugate sulphates and glucuronates and are thus 

 rendered innocuous. Still other substances, moreover, which are for- 

 eign to the body, such as various metallic salts and certain alkaloids, 

 are here removed from the general circulation when artificially intro- 

 duced, and it is for this reason also that the hypodermic injection 

 of such substances is much more efficacious than their administra- 

 tion by the mouth. The subsequent elimination of the metallic salts 

 then occurs in part through the bile, and to a great extent also 

 through the intestinal epithelium. The alkaloids are similarly re- 

 moved, and also appear in the urine in a more or less modified form. 



Formerly it was supposed that the retransformation of peptones 

 into native albumins occurred in the liver, but, as I have shown, 

 this is not the case. On the other hand, we have seen that the carbo- 

 hydrates after their transformation into monosaccharides are carried 

 to the liver, and are here stored in the form of glycogen when 

 an immediate demand for glucose does not exist on the part of the 

 other organs and tissues of the body. This transformation of mono- 

 saccharides into glycogen represents one of the most important syn- 

 theses which occur in the animal body, and it is interesting to note 

 that whereas glycogen on decomposition always gives rise to the for- 

 mation of glucose, the liver is capable of transforming the other 

 monosaccharides into glycogen as well (see also page 167.) 



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